time: 2021.3
# -*- coding: utf-8 -*-
# @Time    : 2021/4/15 19:56
# @Author  : luogan
# @Email   : 468640092@qq.com
# @File    : test01.py
# @Software: PyCharm.
while len():
    if str.isalnum():
        print(str)
    else:
        print(str)